Question

我正在使用PHP为MySQL数据库构建一个小型Web界面。一个任务是允许用户能够将字符串输入到文本字段中，系统应该返回名称中包含该字符串的任何表的名称。但是，我的问题是，每次进入Web界面时，它都会默认显示所有表名。这是我的完整代码。

<!DOCTYPE html>
<html>
<head>
      <meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<style>
.error {color: #FF0000;}
</style>
<body>

<h1>This is H1</h1>

<?php

$servername = "xxx";
$username = "xxx";
$password = xxx;

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
 die("Connection failed: " . $conn->connect_error);
 }

?>

<?php
$search = $searchErr = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    if (empty($_POST["search"])) {
        $searchErr = "Search keyword is required";
    } else {
        $search = test_input($_POST["search"]);
        if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
            $nameErr = "Only letters and white space allowed";}
        }
    }

    function test_input($data) {
        $data = trim($data);
        $data = stripslashes($data);
        $data = htmlspecialchars($data);
        return $data;
    }
?>

<h2>Search Keyword</h2>
<p><span class="error">* required field.</span></p>
<form method="post" action="<?php echo     htmlspecialchars($_SERVER["PHP_SELF"]);?>">
Search: <input type="text" name="search" value="<?php echo $search;?>">
<span class="error">* <?php echo $searchErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit"> </form>

<?php
    echo '<h2> Search Result: </h2>';
    $searchSQL = "SELECT table_name FROM information_schema.tables
                  WHERE LOWER(table_name) LIKE LOWER('%$search%') 
                  AND table_schema = 'xxx'";

    $result = $conn->query($searchSQL);

    echo '<form method="POST" action="show_columns.php">'; // opening form tag

    if ($result->num_rows > 0) {
        // output data of each row
        while($row = $result->fetch_assoc()) {
            $table_name = $row['table_name'];
            echo "<input type='submit' name='table_name' value='$table_name' /> <br/>";
        }
    } else {
        echo ' ';
    }

    echo '</form>'; // closing form tag
?>

</body>
</html>

例如，每次进入Web端时，搜索结果都会显示所有表名。我假设它可能需要空字符串作为搜索关键字？有关如何解决它的任何想法？提前谢谢！

Answer 1

这可能不是最干净的解决方案，但我在执行搜索查询之前添加了一个条件

if ($search!='') 
  {$result = $conn->query($searchSQL);}
else {...}
...

问题解决了。感谢您的所有建议。

使用php显示无结果作为默认值

1 个答案: